The key on the left obviously has damaged buttons. There is no way to prevent this because it depends on how much you use your key. However, you should replace it before its gets this bad or worse.
Why? Because once the buttons break thru like this, then moisture and debris can enter the key and damage it so your car wont start, leaving you stranded! At that point you will need to pay for a service call for us to come to the car to program a new key. And that cost is on top of the cost of the key. If you act quickly, while you can still drive the car, we can make a copy at the shop for about half of what it costs to come to the car.
Give us a call for a free quote.